Multicellular Animals: A New Approach to the Phylogenetic Order in Nature Volume 1No one can ever have secure knowledge about the gods and creatures, and should anyone hit by chance upon the right thing, he will not know it for sure; that is why everything that we believe to be true is "opinion". XENOPHANES around 500 B.C. (According to ROD 1988, p.85) The goal of phylogenetic systematics (cladistics) is to discover the kinship relations between all organisms on earth and to translate the order we perceive in Nature into an equivalent man-made system. Although the goal is easily formulated, the path is thorny, and the results achieved continue to be imperfect. This is the fate of any science that bases its propositions on the interpretation of histor ical evidence. The diversity found in the millions of species originated as a result of the continuous splitting of biopopulations through time. Combined with this was the emergence of hierarchically linked des cent communities of species. We call the process of origin of descent communities phylogenesis. We do not know, however, the exact course of phylogenesis - we can only formulate hypotheses. The historical evidence at hand consists of the feature patterns of extant species and of extinct species with their combination of original and derived traits which are the result of evolution. |
Contents
Introduction | 9 |
Establishing the Phylogenetic System | 22 |
Problematic Large Divisions of Organisms | 47 |
Copyright | |
9 other sections not shown
Other editions - View all
Multicellular Animals: A new Approach to the Phylogenetic Order in ..., Volume 1 Peter Ax Limited preview - 2012 |
Common terms and phrases
accessory centriole aciliated Acoela Acoelomorpha adelphotaxa Annelida Anthozoa apomorphy auditory ossicles Autapomorphies Fig autapomorphy BARTOLOMAEUS basal body Bilateria canal cell Catenulida centriole Cestoda choanocytes cilia ciliary rootlet cilium cleavage Cnidaria coelom congruences cross section Ctenophora Cubozoa Demospongea descent community Diagram Digenea dorsal ectoderm ectoderm and endoderm EHLERS endoderm epidermal cells epidermis Epitheliozoa epithelium Eumetazoa Euspiralia evolution evolutionary novelties evolved free-living glands glandular cells Gnathostomulida gonad ground pattern hermaphrodite Hydrozoa hypothesis individual intestine kinship relations larva longitudinal muscles Mammalia medusa Metazoa microvilli monociliated Monogenea monophyla monophylum multiciliated muscle cells musculature Nemertini Nemertodermatida Neodermata Neoophora nerve original parasites pharynx phylogenetic kinship phylogenetic system Placozoa Plathelminthes Plathelminthomorpha plesiomorphy Polycladida polyp pore Porifera proboscis protonephridia Radialia Rhabditophora Scyphozoa secondary body cavity sensory septa sister group sperm Spiralia sponges statocyst statolith stem lineage stem species stylet synapomorphy systematics taxa taxon tentacles terminal cell Trematoda ultrastructure unicellular unity ventral vitellocytes